Various means have been used in the past to fasten a bearing into the hub of a pulley or other rotary object which has been formed by splitting a circular disk and spin forming the blank into a pulley shape. A separate bearing housing is then attached to the pulley by welding staking or the like. The bearing housing is formed as two cup shaped housing which are fastened together by welding, rivets or the like to hold the bearing in place. Another means of fastening a bearing in a pulley is shown in U.S. Pat. Nos. 3,758,930 and 3,828,619 both of which are issued to Charles C Frost et al. In both these patents, a pulley is formed by typical metal splitting techniques having a central hub for receiving a bearing. The hub is formed with two axially extending annular flanges, with one being crimped radially inwardly at the same time it is formed as shown in FIG. 4 of the '930 patent to retain one side of a bearing when inserted into the hub, and the other axial flange formed extending straight axially outwardly, then later crimped around the bearing in a separate operation.
It has been found, however, that crimping each of the flanges in two separate operations does not provide as tight a fit around the bearing as when the flanges are crimped simultaneously after press fitting the bearing into the hub, since there is less area of surface contact between the hub and the bearing as shown in FIGS. 6 and 7 of the '930 patent where it can be seen that there is no surface contact between the outer circumference of the bearing except where it is crimped around the outer circumferential corners of the bearing. The angle formed by the split between the hub flanges of the '930 patent allows the flanges to bend and open up upon continued use of the bearing and hub assembly. This causes the bearing to become loose and wobbly within the hub.
In contrast to the '930 patent, in the present invention, as shown in FIGS. 5 and 6 of this application, there is about 80% surface contact between the outside circumference of the bearing and the inside circumference of the hub flanges. Since the hub flanges extend axially straight until the crimped ends there is less separation of the hub flanges upon use of the bearing and less likelihood of loosening of the bearing within the hub.
In U.S. Pat. No. 5,979,203 issued to Mijo Radocaj, the present inventor has invented a machine for splitting and spin forming a disk blank into a pulley having a hub which is particularly useful in carrying out the steps of the present invention.